#include<cmath>
#include<iostream>
using namespace std;
const long double m = 654.49, c = 377, h = 4.03, k = -0.0227;
const long double hp = 10.02, dp = 98.20, t1 = 67.562, t2 = 58.3;
const long double PI = 3.1415926, d = 99.6;
int main()
{
	long double s = 4 * m * c * h * k * (4 * hp + dp) / (t1 - t2) / PI / d / d / (4 * hp + 2 * dp);
	printf("%lf", &s);
	return 0;
}